The additive manufacturing process is widely known as “3D printing.” Numerous 3D-printing methodologies have been described in prior art, the most common being solid-laser sintering (SLS), stereolithography (SLA), and extrusion-based 3D printing or fused filament fabrication (FFF).
All of these methods involve depositing a thin layer of thermoplastic or thermoset materials. In FFF, thin strands of material (referred to herein as “extrudate”) are deposited from a deposition nozzle onto a build surface. As the filament moves through the FFF system, it undergoes mechanical, chemical, and thermal changes. Deposition proceeds in a controlled pattern on the build surface to construct a 3D object.
In operation of an FFF system, a filament of material is fed into a nozzle manifold via a motorized feed system from a supply spool. This spooled material is typically at room temperature in a solid state. Typically, the filament moves through the manifold into a cooling block, and then a heating block. As the filament moves through the heating block, it is heated above a melting temperature. Once melted, the polymer is in a completely liquid, free-flowing state and exits the nozzle.
Once the liquefied polymer (extrudate) reaches the build surface (or is deposited on already-deposited layers of extrudate), it cools below its crystallization temperature. If the build chamber and build platform are maintained at the appropriate temperature, the polymer chains in the extrudate begin to order and align before completely solidifying. Once the build is complete, the polymer cools down to room temperature.
The thermal management of the filament throughout the FFF process is critical for building, in a consistent and predictable fashion, 3D objects. The management of and interplay between the cooling and heating blocks must be tightly controlled to ensure proper deposition, cooling and solidification of the build. For example, it is clear that the heating block must be maintained above the processing or melt temperature of the polymer for the filament to melt and extrude through a small orifice (e.g., diameter between about 0.1 to 0.5 mm) in the nozzle. Furthermore, the temperature in the cooling block, which would otherwise rise due to heat conducted thereto from the heating block, must be kept below the processing/melt temperature.
The prior art provided for controlling the temperature of the cooling block using a fan that is attached directly to the cooling block, or by circulating a cooling liquid around the cooling block or nozzle manifold. This removes heat from the cooling block and is able to keep the temperature in the cooling block below processing/melt temperature of the polymer feed.
The ability to provide this critical temperature control becomes particularly difficult when high-temperature polymers such as polyether ether ketone (PEEK), polyamide-imine (PAI) and self-reinforced polyphenylene (SRP) are being processed for deposition. The cooling block must be capable of removing significant amounts of thermal energy from the nozzle manifold in a very controlled manner. A need therefore exists for a system and method to provide such reliable, controllable and efficient means to cool an FFF nozzle manifold adapted to deposit high-temperature polymers such as PEEK, PAI, and SRP.